Tower defense games never get old. With an abundant choice of such time-wasters available for iOS devices, there are a few that manage to stand out from the rest and demand respect. Defense zone HD comes as a fresh breeze for the tower defense genre, with a very simple gameplay and controls that one grows to understand in a few minutes. With graphics and animations worth awing at, and destruction satisfaction at its best, Defense zone will keep you occupied for hours as it begins challenging your strategies moving through the levels. The difficulty, unless you play with the it set to Easy, will mess with your head, enough to make you want to strangle someone. More about the game after the break.

Note:Defense zone HD has a price tag of $2.99 on the App Store. We’re giving away five promo codes for the game to 5 lucky readers, details for which can be found at the end of this post.

What’s the concept? Well, there’s no storyline here, so you will have to make one up in your head if you badly need that (World War 3, maybe?). Usual maps, coupled with defense turrets that can be upgraded, are all that matters.

The game has 10 maps in total, taking you from the desert to the ice caps and volcanoes. With each level, the enemy waves increase as well, not to mention the amount and difficulty. The graphics, as can be seen, while not exactly high resolution, are in fact pretty nifty, and you won’t be disappointed.

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The basic Gatling Gun, Rocket Turret (air defense), Liquid Nitrogen, Lightning Bolt, Flame Thrower and Mortar are the turrets of choice. Most of these will be locked once you start, but as you progress through the levels, newer turrets will be unlocked. For every enemy you kill, you gain credit, and with that credit, you can buy and place the turrets on the prescribed areas on the map. More so, you have the option to upgrade your turrets – something you won’t be able to survive without. Turrets can be assigned to attack the weakest targets, nearest, or strongest. A word of advice, the Liquid Nitrogen turret in use with a Flame Thrower turret is not a smart idea, as both of their effects will be nullified, exactly as you would expect in the real world.

Once you place or tap a turret, you will see two highlighted radiuses. The smaller one is the area the turret covers when placed, and the larger, of course, is its range. Upgrading will increase that, along with firepower and rate of fire. Tapping a turret also reveals a panel to the right side, where you can sell the turret, upgrade it, and assign its attack orders. The same panel also states a turrets current firepower and range, as well as the advantage that you will gain by upgrading it. In a hurry? Press the Fast Forward button next to the Configuration button in the bottom panel for a 2x increase in the simulation speed. In the event that you get tired – considering the last level lasts for 40 waves – you can always Save & Exit.

Giveaway: We’re giving away 5 promo codes for the full version of this game. The giveaway will last for 24 hours. Participation is simple. Follow @addtips on Twitter, tweet/retweet the giveaway and in the comments below, provide a link to your tweet. Alternatively, you may comment on our Facebook or Google+ page, where the comment should preferably be under the shared post and not on the page itself. Our editors will pick the five winners randomly.

Update: Giveaway has been closed and promo codes have been sent to the winners. If you entered for the giveaway, please check your Facebook messages, Twitter direct messages and/or Google+ feed.